Touchscreen modules comprise touch sensitive panels superimposed over a display, so that a user can select an object (for example, text or graphics) presented on the display by touching the corresponding point on the touch sensitive panel. A touch panel controller ascertains co-ordinates of a point touched by the user and provides the co-ordinates of this point to an operating system.
A touchscreen module can be based on any one of a variety of different technologies, such as resistive, capacitive, surface acoustic wave, and the like. Irrespective of the technology used, all touchscreen modules require to be calibrated so that an application can correlate a position touched on the touch panel with an element presented on the display. This calibration process is usually performed before the touchscreen module is used, and may also be performed at time intervals if the touch panel calibration is prone to drifting. The calibration process results in calibration parameters that are stored in an operating system registry. These calibration parameters are used to compensate for any offset between an actual point touched and point sensed by the touch panel controller.
When a new touchscreen module is installed in a terminal, such as an automated teller machine (ATM), then the touch panel must be calibrated, which is inefficient and time consuming. Furthermore, variations between touchscreen modules may be so great that the calibration parameters for one touchscreen module, when applied to a new touchscreen module, may make it very difficult for a person to use the new touchscreen module even to initiate the calibration process.
Some touchscreen modules include a special non-volatile memory associated with the touch panel for storing the calibration parameters so that a newly-installed touchscreen module does not need to be calibrated. However, these touchscreen modules may not be compatible with some hardware and software used in the terminal in which the touchscreen module is mounted.
It is among the embodiments of an embodiment of the present invention to be able to store calibration parameters without requiring a special non-volatile memory associated with the touch panel.